There are two names that have been applied to ancient India's first phase of urbanization - Harappan civilization or Indus civilization. The first of these is derived from an academic tradition which uses a type specimen, or site, as the basis for nomenclature in archaeology.
Since the mounds adjacent to the modern village of Harappa were the first locality where the remains of this civilization were first identified, the name Harappan fits such a system perfectly. The second name, Indus civilization is used interchangeably.
Firstly because it refers to precisely the same cultural, chronological and geographic entity and secondly because it started from the river valley of the Indus River and the largest concentration of settlement sites are located along the course of this river sir John Marshall was the first scholar to use this term.
While both these terms can be justified in some ways, neither of them is without shortcomings. For example, the very notion of the Indus civilization in Saurashtra (Gujarata) is out of place in view of the fact that it is reasonably beyond the geographic bounds of the Indus valley, as are Haryana, Indian Punjab and Western Uttar Pradesh, where the remains of Indus civilization were found. The term Harappan civilization, conjures up a notion that the civilization began at a site which best represents the ancient urban system of South Asia.
The Indus civilization belongs to the proto- historic period since it represents a phase in which people had developed a script and written records are available but the script has not been deciphered as yet despite repeated attempts.
Although some scholars are inclined to place Indus civilization in the category of chalcolithic state but majority thinks that chalcolithic groups were primarily rural farming communities with knowledge of copper, the first metal to be used by mankind. Technologically speaking chalcolithic stage applied to the pre-Harappans and many post-Harappans because they mostly used stone and copper objects, although they very occasionally used low-grade bronze.
On the other hand, the Harappans used bronze on a large scale and were urban in character. One might expect that left to its own resources, the internal development in the chalcolithic period would in due course have led to urbanization. So it is agreed that the Indus civilization belonged to Bronze Age, generally associated with city formation.
Source :
http://www.preservearticles.com/2011101915685/what-are-the-feature-of-nomenclature-of-indus-civilization.html
